Method of and apparatus for wireless telephony and telegraphy.



C. D. EHRET.

METHOD OF AND APPARATUS FOR WIRELESS TELEPHONY AND TELEGRAPHY.

APPLICATIDN FILED FEB. 3, 1909.

1,1 84,434. Patented May 23, 1916.

(W, i M 24am UNITED STATES PATENT OFFICE.

CORNELIUS D. EHRET, OF PHILADELPHIA, PENNSYLVANIA.

Specification of Letters Patent.

Patented May 23, 1916.

Application filed February 3, 1909. Serial N 0. 475,792.

To alder/10m it may concern Be it known that I, Couxnmus D. Enun' a citizen of the United States, residing at Philadelphia, county of Philadelphia, and State of Pennsylvania, have invented certain new and useful Improvements in Methods of and Apparatus for lVireless Telephony and Telegraphy. of which the following is a specification.

y invention relates to a method of and apparatus for telephonic, telegraphic, or other communication by means of electrical waves transmitted through the natural media. I

My invention relates to a system of wireless telephony wherein there are constantly impressed upon the natural media groups of electrical waves, the group frequency for telephony being above the limit of audition, or continuous or substantially continuous waves. as derived from sustained or practically sustained oscillations. And the waves so transmitted are modified by and in accordance with speech through the instrumentality of an associated circuit producing continuous or sustained oscillations, the energy of the last mentioned circuit being controlled either as to amplitude or frequency by a suitable telephone transmitter.

My invention resides in features of method and apparatus hereinafter described and pointed out in the claims.

For an illustration of some of the forms my invention may take. reference is to be had to the accompapying drawing, in which:

Figure 1 is a diagrammatic view of transmitting apparatus in which there is a continuously operating producer of groups of waves or oscillations. associated with a pro ducer of sustained or continuous oscillations or \HH'PS. the latter icing telegraphically or telephonically controlled. Fig. 2 is :1 diagrammatic view illustrating a producer of continuous or sustained oscillations associated'with another producer of sustained or continuous oscillations. the latter being provided with telegraphic or telephonic controlling apparatus. Fig. 3 illustrates diagramniatically a receiving apparatus in which adynamomcter" telephone receiver is employed. and in connection with which a "olnlenser or clectro-static telephone may no employed. Fig. l is a diagrammatic view of receiving apparatus suitable for receiving wireless telephonic or telegraphic messages as transmitted by the transmitting apparatus herein described. Fig. 5 is a diagrammatic view in which the received energy rectified and employed to affect or control a suitable instrument.

In Fig. 1, A represents an aerial conductor between which and the earth E is connected an adjustable winding or coil L which may serve as the secondary of a transformer whose adjustable primary P is included in circuit with the adjustable condenser K and the spark gap 8, the secondary S of a step-np transformer being connected across the terminals of the spark gap 8. P is the primary of the transformer and is traversed by alternating or fluctuating current derived from the source of generator G, the frequency being such that the groups of resulting oscillations in the circuit containing P and K succeed each other at such rate or have a frequency as to be above the limit of audition for telephony. This producer of groups of oscillations may be of relatively high power and operate continuously without being controlled or affected by any signaling instrument. Also associated with the inductance or secondary L is another adjustable primary coil or winding 1, which forms the inductance element of a circuit including the adjustable condenser K and the are a, the latter being fed by preferably direct current from the generator G, which may be controlled by the adjustable resist: ance r, choke coils I), 7) being provided to prevent high frequency oscillations from passing to the generator circuit.

The primary P may be either closely or loosely coupled with the inductance or secondary L; and similarly, the primary P may be either loosely or closely coupled with 1. And P and P may be either loosely or closely coupled with each other, and when either loosely or closely coupled with each other, may be either loosely or closely coupled with L.

A telephone transmitter T is included in the sustained oscillation circuit K a, P and may be of the microphone or other suitable type.

The operation is. then, as follows: The right hand oscillation generator keeps im- .tuation of the frequency aerial A groups of high the group frequency being above audition. Superposed, as it were, upon this energy, or modifying such energy, as it is impressed upon the aerial A, is the energy of the sustained or continuous oscillations of the arc circuit, and this circuit may supply relatively small energy which is easily controlled by the telephone transmitter T. This energy is so modified by and in accordance with speech that it correspondingly modifies the high power energy impressed upon the aerial A by the right hand oscillation producer. By this means great amounts of energy may be transmitted and yet successfully controlled by a telephone transmitter.

The telephone transmitter T varies the amplitude of the energy in the arc circuit and of the transmitted energy. This telepressing upon the power oscillations,

.phone transmitter may be taken out of action, however, by closing the switch 0 In which case the transmitter T is short circuited. In such case, the switch (Z may be closed, which then brings the telephone condenser K into parallel relation with the condenser K In such case, speech uttered against the condenser K produces a flucof the sustained or continuous oscillations, such changes in frequency being in accordance with the fluctuations in speech or sound waves. In such case, the normally transmitted energy of high power from the right hand oscillation producer is modified by the relatively lower power continuous osci lations, which, however, are changing in frequency under the influence of the voice and in accordance with the voice. Or, in place of closing the switch d, the switch 0 may be closed, in which case a telephone transmitter T is brought into circuit with an adjustable portion of the winding or coil 1. This portion being external to the portion included in the arc circuit, the arrangement may be considered as an auto-transformer. Speech uttered against the transmitter 'I' will control the continuous or sustained oscillations and, in effect, control the high power transmitted energy by and in accordance with speech;

For telegraphy, the transmitter .T or transmitter. '1 may be replaced by a key; or switch (1 may be replaced by a key.

In Fig. 2 the partsare the same as in Fig. 1 as to the left hand oscillation producer,that is, the producer of sustained or continuous oscillations. Instead, however, of a producer of groups of oscillations, a producer of continuous or sustained oscillations is provided at the right and comprises the primary P, operating as tance, a. variable condenser K and the are a, which is fed by the generator G, preferably of direct current, through the adjustable rebefore as an inducsistance r and the choke coils b, b. In this case, the right hand oscillation producer may be of relatively high power and continuously impressed uponthe aerial A sustained oscillations. Then, by the relatively lower power oscillation producer at the left, the transmitted energy is varied by and in ac cordance with speech, as described in connection with Fig. I.

In Fig. 2 G and G may be one and the same source, the different are circuits deriving their energy from the same source. And as in Fig. 1, the telephone transmitters may be replaced by keys for telegraphy.

In Fig. 1 the normal frequency of the arc circuit may be equal to, greater than, or less than the frequency of the oscillations generated by the right hand producer. And where the condenser K is used for varying the frequency of the arc circuit in accordance with speech, the normal frequency of the arc circuit may be equal to, greater than, or less than the frequency of the oscillations produced by the right hand pro lucer. And in Fig. 2, the frequencies of the two are circuits may be the same, or the frequency of one may be greater than or less than the other. And, in the case where the telephone condenser K is used to vary the frequency of the left hand arc circuit by and in accordance with speech, the normal frequency of the left hand circuit may be equal to, greater than, or less than the frequency of the right hand circuit. And while it has been stated that the right hand producers in both Figs. 1 and 2 are preferably of higher power than the left hand producers, it is to be understood that I do not wish to be limited in this regard, inasmuch as the right and left hand producers may be of equal powers, or, in some cases, the left hand producers may be of greater power than the right hand producers.

In Fig. 3 A represents a receivin aerial conductor between which and earth is connected a variable primary L with which is inductively related, either by loose or close coupling, a secondary L In the secondary circuit is included a closed, preferably resonant, circuit comprising the condenser K, which with the serially connected coils L, L may reduce tuning or resonant effects. With transmitted continuous or sustained oscillations, controlled either telegraph key or telephone transmitter, the coils L and L may be flat coils, one stationary and the other connected to a diaphragm to form a telephonic receiver whereby speech may be reproduced or telegraphic signals may be reproduced. And the condenser K may be an electro-statie telephone which may be then used as a telephone receiver to reproduce speech or to reby aproduce telegraphic signals. While this arrangement is useful in connection with sustained or continuous oscillations, it is useful also in the case of transmitted groups of waves or oscillations.

In Fig. 4 there is represented a receiving arrangement in which the primary L has associated therewith a secondary L which is connected in circuit with an adjustable or variable condenser K, W being self-restoring wave-responsive device of any suitable type, such, for example, as a primary cell detector, and T is an ordinary magneto or other telephone receiver. This arrangement may be used with either of the transmitting apparatus shown, either for telephony o1 telegraphy.

In Fig. 5, the secondary L is connected in circuit with the variable condenser K and the detector V comprising a metallic member n and a mass of silicon, fused zinc oxid, or other material a forming a thermoelectric detector, and in place of V may be substituted any other detector which will produce a rectification of either continuous or sustained, oscillations, 0r oscillations in groups. The rectified energy passes into the circuit containing the choke coils b, b, for keeping out the high frequency oscillations, and such energy may be used to charge a secondary or storage cell m, which may, then, dischar e through a telephone receiver T or any ot ier suitable device, and an interrupter 2'- may intervene.

In place of the are devices shown for producing sustained or continuous oscillations, other means may sustained or practically continuous oscillations.

IVhat I claim is:

1. The method of electrically transmitting intelligence through space, which consists in generating high frequency oscillations of high power. separately generating high he quency oscillations of low power, controlling said oscillations of low power to represent a signal or message, impressing energy of said high and low power oscillations in superposed relation upon the natural media, and reproducing the signal or message by the conjoint action of the received energy of said high and low power oscillations.

2. The method of electrically transmitting Speech through space, which consists in generating high frequency oscillations, separately generating other high frequency oscillations, controlling the separately generated oscillations independently of said .first named oscillations by and in accordance with speech, and impressing energy of all said oscillations upon the natural media.

3. The method of electrically transmitting speech through space, which consists in generatii ig practically continuous electrical oscillations, separately generating other pracbe employed for producing tically continuous oscillations, controlling the separately generated oscillations independently of said first named oscillations by and in accordance with speech, and simultaneously and independently impressing energy of all said oscillations upon the natural media.

4. The method of electrically transmitting speech through space, which consists in generating practically continuous oscillations of high power, separately generating other practically continuous oscillations of lower power, controlling the oscillations of lower power by and in accordance with speech, and impressing the resultant energy upon the natural media.

5. Ina system for transmitting intelligence through space, the combination with means forproducing high frequency oscillations, of means for producing other high he uency oscillations, means for changing the frequency of only said second named oscillations to represent a signal or message, and means for impressing resultant energy of said first and second named oscillations on the natural media.

6. In a wireless telephone system, means for continuously generating hi h frequency oscillations, means for separate y generating other high frequency oscillations, means for controlling the separately generated oscillations independently of said first named oscillations by and in accordance with speech, and means for simultaneously and independently impressing energy of all said oscillations upon the natural media.

7. In a wireless telephone system, means for generating substantially continuous high frequency oscillations, means for separately generating other oscillations, means for superposing the separately gene 'ated oscillations upon said first mentioned oscillations, and means for controlling said separately enerated oscillations independently of said first named oscillations by and in accordance with speech.

8. In a system for gence through space,

transmitting intellithe combination with means for producing high frequency oscillations, of means for producing other high frequency oscillations, means for changing the frequency of only said second named oscillations to represent a signal or message, and means for impressing resultant energy of said first and second named oscillations on the natural media, the frequency of said second named oscillations when representing the signal or message diflering from the frequency of said first named oscillations.

9. The method of electrically transmitting intelligence through space, which consists in simultaneously generating a plurality of trains of high frequency oscillations and im pressing their energy upon the natural media 111 superposed relation, and changing the frequency of the oscillations of less than all of said plurality of trains to represent a signal or message.

10. The combination with a radiating conductor, of an oscillation circuit including an arc, a second oscillation circuit independently associated with said radiating conductor and including an arc, and a signaling instrument controlling one only of said oscillation circuits, said oscillation circuits impressing high fre uency oscillations upon said radiating con uctor. 11.'The method of electrically transmitting intell gence through space, which consists in simultaneously generating a plu rality of trains of high frequency oscillations and impressing their energy upon the natural media in superposed relation, and changing the frequency of the oscillations of less than all of said plurality of trains to represent a signal or message, the frequency of said last named oscillations when representing the signal or message differing from the frequency of the oscillations of another of said plurality of strains.

12. The method of electrically transmitting intelligence through space, which consists in simultaneousl generating high frequency oscillations 0 high and low powers and impressing their energy in superposed relation upon the natural media, and changing the frequency of the oscillations of low power to represent a signal or message 13. The method of electrically transmitting intelligence through space, which consists in simultaneously generating high frequency oscillations of hlgh and low powers and impressing their energy in superposed relationupon the natural media, and changing the frequency of the oscillations of low power to represent a signal or message, the frequency of said oscillations of low power when representing the signal or message differing from the frequency of the oscillations of high power 14. The combination with a radiating conductor, of a high frequency oscillation circuit associated therewith, a second high frequency oscillation circuit in inductive relation with said radiating conductor, and a telephone transmitter controlling only said second oscillation circuit.

15. The method of electrically transmitting speech through space, which consists in generating high frequency oscillations of high fpower, separately generating other high requency oscillations of low power, controlling the frequency of said low-power oscillations independently of said high power oscillations by and in accordance with speech, and simultaneously impressing energy of said high and low power oscillations upon the natural media.

16. The combination with a radiating conductor, of means continuously operating for impressing oscillations thereon, further means for superposing oscillation 5 upon said first mentioned oscillations, and a telephone transmitter controlling only said last mentioned means.

17. The combination with a radiating conductor, of a plurality of oscillation circuits inductively related therewith and simultaneously impressing their energies thereon, said oscillation circuits having different degrees of coupling with said radiating conductor, a signaling instrument controlling one of said oscillation circuits, and another of said oscillation circuits operating independently of control by said signaling instrument.

18. The combination with a radiator, of means for generating high frequency high power oscillations, means for separately generating high frequency low power oscillations, and signaling means controlling only said low power oscillations.

19. means for generating high frequency high power oscillations, means for separately generating high frequency low power oscillations, and telephonic transmitting means controlling only said low power oscillations.

20. The method of transmitting intelligence, which consists in generating high frequency high power oscillations, separately generating high frequency low power oscillations, controlling said low power 03- cillations independently of said high power oscillations to represent a signal or message, and impressing energy of said high and low power oscillations upon the natural media.

21. The combination with a radiating conductor, of a plurality of independent oscillation producers impressing energy upon said conductor, at least one of said oscillation producers operating continuously, and means for varying the frequency of the oscillations of another of said producers to represent a signal or message.

22. The combination witharadiating conductor, of an oscillation transformer secondary connected therein, a plurality of Midfipendent oscillation circuits each having a transformer primary cooperating with sai secondary, said transformer primary circuits being loosely coupled with respect to each other, one of said oscillation circuits operating continuously, and a signaling in strument controlling another of said oscillation circuits.

23. The combination witha radiating con-- ductor, of an oscillation transformer secondary connected therein, a plurality of independent oscillation circuits eachhaving a transformer primary cooperating with said secondary, said transformer primary circuits being loosely coupled with respect to each other, one of said oscillation circuits The combination with a radiator, of.

operating continuously, and a signaling instrument for varying the frequency of the oscillations of another of said circuits.

24. The method of electrically transmitting speech through space, which consists in generating high frequency oscillations, separately generating other hi h frequency oscillations, controlling the i i'equency of said separately generated oscillations independ- 19 ently of said first named oscillations by and in accordance with speech, and simultaneously impressing energy of all said oscillations upon the natural media.

In testimony whereof I have hereunto affixed my signature in the presence of the 1 two subscribing witnesses.

CORNELIUS D. EHRET. Witnesses:

DANIEL WEBSTER, Jr., A. E. STEINBOCK.

Corrections in Letters Patent No. 1.184.434.

operating continuously, and a signaling instrument for varying the frequency of the oscillations of another of said circuits.

24. The method of electrically transmitting speech through space, which consists in generating high frequency oscillations, separately generating other hi h frequency oscillations, controlling the iiequency of said separately generated oscillations independ- 1 ently of said first named oscillations by and [aura] Signed and sealed this 20th day of June, A. 1)., 191 6.

in accordance with speech, and simultaneously impressing energy of all sald osclllations upon the natural media.

In testimony whereof I have hereunto aflixed my signature in the presence of the 1,

It is hereby certified that in Letters Patent No; 1,184,434, granted May 23, 1916, upon the application of Cornelius D. Ehret, of Philadelphia, Pennsylvania, for an improvement in Methods of and Apparatus for Wireless Telephony and I :Telegraphy, errors appearin the printed specification requiring correction as follows: Page 1, line 72, for the word of read or; page 2, line 69, for theword' vimpressed read impress; page 4, line 25, claim 11, for the word strains-rcad trains; and thatthe said Letters Patent should read with these correct-ions therein that the same may conform to the record of the case in the Patent Oflice.

J. T. miwfron, Acting Commissioner of It is hereby certified that in Letters Patent No 1,184,434, granted May 23,

1916, upon the application of Cornelius D. Ehret, of Philadelphia, Pennsylvania, for an improvement in Methods of and Apparatus for Wireless Telephony and Telegraphy, errors appear in the printed specification requiring correction as follows: Page 1, line 72, for the word of read or; page 2, line 69, for theword impressed" read impress; page 4, line 25, claim 11, for the word "strains read trains; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Oflice.

Signed and sealed this 20th day of June, A. D., 191 6.

J. T. NEWTON, Acting Oommiun'mwr of Patents.

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